The present invention relates to aviation maintenance, repair, and overhaul, and more particularly to access equipment for repair of large engine components including blocker door assemblies.
Presently, there is no safe procedure for accessing and removing the upper blocker door assemblies. There have been creative, labor intensive and unsafe methods to gain access to these doors.
A prior method was created for the 747-400 Rolls Royce engine in 1991. This tool was very expensive and was dedicated only to one engine use.
Some include stacking unmounted automobile tires as needed inside the fan duct and climbing up the tires to the location they need to get to. This method is very hazardous and unstable tires can collapse and injure personnel as well as add foreign object debris (FOD) risk to inside of the fan duct.
Another method is to double up heavy 2xe2x80x3 by 8xe2x80x3 wood boards and secure them to fork lift tines and move the board into the fan duct using a hydraulic fork lift, which has an envelope of around 24xe2x80x3 between the outer thrust reverser (T/R) sleeve and inner fan duct wall. This procedure is risky because a mechanic can easily damage composite acoustic paneling with the wood board, introduce FOD, and the mechanic is also taking a safety risk on the board cantilevered out that far to reach the blocker door.
Another method is to totally remove the T/R from the engine and put it in a laydown position on the ground and translate the T/R sleeve open. This may be the safest way but most uneconomical since one has to completely remove the T/R from the engine, perform the repair and then reinstall the T/R, which adds more man hours to perform the job and an increase of actual mechanics to perform the installation/removal process and involves use of extra overhead handling equipment.
Aviation maintenance repair and overhaul organizations need to perform routine checks and sometimes necessary repair in areas that are not conducive to off the shelf, commercially available access equipment such as ladders and scaffolding. There is also the environment of the repair area to consider since many areas pose potential fall hazards and sometimes expensive damage to composite structure, fabrics (interiors), and electrical equipment. There are times when special access equipment must be designed to perform these repair tasks in these confined and load critical areas.
Access to all replaceable components (i.e., blocker doors, door links, acoustic wedge panels between blocker doors) on the large engines of the 777, which include GE, Pratt Whitney and Rolls Royce, has become more difficult due to the larger overall diameter growth of these engines. The 777 thrust reverser (T/R) design uses blocker doors that flip out and deflect thrust forward when the T/R is deployed during landing. These doors are stationed radially inside the fan duct and access to them for removal is difficult especially for the upper half. The highest door is about 13 feet off the ground and one has to go inside the fan duct about 4 feet to get to the door for access to the hinges.
Accordingly, it is an object of the present invention to provide a T/R blocker door access platform tool whick allows a mechanic to gain access to any door needed for removal and installation in a safe manner. The fan duct""s acoustic composite paneling is easily susceptable to foreign object damage (FOD) and marring from sharp edges of conventional ladders.
The hereinafter described access platform is made of polyurethane foam blocks which resist FOD being picked up by it such as gravel, metal shavings, etc., and is lightweight by incorporating a styrofoam core, since a single person must get inside the fan duct, which is a confined space and assemble the platform themselves to scale up on.